部份中文华法林钠处方资料（仅供参考）
【药品名称】华法林钠片
【通用名称】华法令、华法林
【英文名称】Warfarin Sodium Tablets
【中文拼音】Warfarin
【功能与主治】
华法林钠片Warfarin适用于需长期持续抗凝的患者：
1．能防止血栓的形成及发展，用于治疗血栓栓塞性疾病；
2．治疗手术后或创伤后的静脉血栓形成，并可作心肌梗死的辅助用药；
3．对曾有血栓栓塞病患者及有术后血栓并发症危险者，可予预防性用药。
【型号与规格】
1毫克28片装。
【用法与用量】
口服，成人常用量：避免冲击治疗口服第1～3天3～4mg(年老体弱及糖尿病患者半量即可)，3天后可给维持量一日2.5～5mg(可参考凝血时间调整剂量使INR值达2～3)。因本品起效缓慢，治疗初3天由于血浆抗凝蛋白细胞被抑制可以存在短暂高凝状态，如须立即产生抗凝作用，可在开始同时应用肝素，待本品充分发挥抗凝效果后再停用肝素。
【临床研究】
@阻断VK作用而具抗凝和抗血小板聚集作用；
@本品体外无效，体内需待已合成的凝血因子耗竭后才能发挥作用，故用药早期应与肝素联合用药；
【注意事项】
1．严格掌握适应症，在无凝血酶原测定的条件时，切不可滥用本品。
2．个体差异较大，治疗期间应严密观察病情，并依据凝血酶原时间INR值调整用量。治疗期间还应严密观察口腔黏膜、鼻腔、皮下出血及大便隐血、血尿等，用药期间应避免不必要的手术操作，选期手术者应停药7天，急诊手术者需纠正PTINR值≤1.6，避免过度劳累和易致损伤的活动。
3．若发生轻度出血，或凝血酶原时间已显著延长至正常的2.5倍以上,应即减量或停药。严重出血可静注维生素Kl10～20mg，用以控制出血，必要时可输全血、血浆或凝血酶原复合物。
4．于本品系间接作用抗凝药，半衰期长，给药5～7日后疗效才可稳定，因此，维持量足够与否务必观察5～7天后方能定论
【不良反应及禁忌】
过量易致各种出血。早期表现有瘀斑、紫癜、牙龈出血、鼻衄、伤口出血经久不愈，月经量过多等。出血可发生在任何部位，特别是泌尿和消化道。肠壁血肿可致亚急性肠梗阻，也可见硬膜下颅内血肿和穿刺部位血肿。偶见不良反应有恶心、呕吐、腹泻、瘙痒性皮疹，过敏反应及皮肤坏死。大量口服甚至出现双侧乳房坏死，微血管病或溶血性贫血以及大范围皮肤坏疽；一次量过大的尤其危险。
【禁忌】肝肾功能损害、严重高血压、凝血功能障碍伴有出血倾向、活动性溃疡、外伤、先兆流产、近期手术者禁用。妊娠期禁用。
老年人或月经期应慎用。
【孕妇用药】禁用。
【儿童用药】不明。
【药品相互作用】增强本品抗凝作用的药物有：阿司匹林、水杨酸钠、胰高血糖素、奎尼丁、吲哚美辛、保泰松、奎宁、利尿酸、甲磺丁脲、甲硝唑、别嘌呤醇、红霉素、氯霉素、某些氨基糖苷类抗生素、头孢菌素类、苯碘达隆、西米替丁、氯贝丁酯、右旋甲状腺素、对乙酰氨基酚等。
降低本品抗凝作用的药物：苯妥英钠、巴比妥类、口服避孕药、雌激素、考来烯胺、利福平、维生素K类、氯噻酮、螺内酯、扑痛酮、皮质激素等。
不能与本品合用的药物：盐酸肾上腺素、阿米卡星、维生素B12、间羟胺、缩宫素、盐酸氯丙嗪、盐酸万古霉素等。
本品与水合氯醛合用，其药效和毒性均增强，应减量慎用。维生素K的吸收障碍或合成下降也影响本品的抗凝作用。
【贮藏】常温下避光贮藏。
Warfarin SodiumPronunciation
Class: Anticoagulant
Trade Names
Apo-Warfarin (Canada)
Gen-Warfarin (Canada)
Taro-Warfarin (Canada)
Pharmacology
Interferes with hepatic synthesis of vitamin K–dependent clotting factors, resulting in in vivo depletion of clotting factors II, VII, IX, and X, and proteins C and S.
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Pharmacokinetics
Absorption
Completely absorbed after oral administration. T max is 4 h.
Distribution
Vd is approximately 0.14 L/kg. Approximately 99% bound to plasma protein.
Metabolism
The elimination of warfarin is almost entirely by metabolism. It is metabolized by CYP-450 to inactive hydroxylated metabolites (predominant route) and by reductases to reduced metabolites (warfarin alcohols).
Elimination
The half-life after a single dose is approximately 1 wk; however, the effective half-life ranges from 20 to 60 h. The Cl of R-warfarin is 50% that of S-warfarin. The half-life of R-warfarin is approximately 37 to 89 h and S-warfarin is approximately 21 to 43 h. Approximately 92% of orally administered doses are recovered in the urine.
Onset
Within 24 h.
Peak
72 to 96 h.
Duration
2 to 5 days.
Special Populations
Renal Function Impairment
Renal Cl is a minor determinant of anticoagulant response to warfarin.
Hepatic Function Impairment
Hepatic impairment can potentiate the response to warfarin through impaired synthesis of clotting factors and decreased metabolism of warfarin.
Elderly
Patients 60 y and older appear to exhibit greater than expected INR response to warfarin.
Race
Asian patients may require lower initiation and maintenance doses.
Pharmacogenetics
Vitamin K epoxide reductase (VKORC1) and CYP2C9 gene variants generally explain the largest proportion of known variability in warfarin dose requirements.
Indications and Usage
Prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism; prophylaxis and/or treatment of thromboembolic complications associated with atrial fibrillation and/or cardiac valve replacement; reduction of risk of death, recurrent MI, and thromboembolic events such as stroke or systemic embolism after MI.
Unlabeled Uses
Primary venous thromboembolism prophylaxis in cancer patients; venous thromboembolism prophylaxis in cancer patients with a central venous catheter.
Contraindications
Pregnancy, except in pregnant women with mechanical heart valves who are at high risk of thromboembolism; hemorrhagic tendencies or blood dyscrasias; recent or contemplated surgery of the CNS or eye, or traumatic surgery resulting in large open surfaces; bleeding tendencies associated with active ulceration or overt bleeding of GI, GU, or respiratory tracts; CNS hemorrhage; cerebral aneurysms; dissecting aorta; pericarditis and pericardial effusions; bacterial endocarditis; threatened abortion; eclampsia and preeclampsia; spinal puncture and other diagnostic or therapeutic procedures with potential for uncontrolled bleeding; major regional or lumbar block anesthesia; malignant hypertension; unsupervised patients with conditions associated with a potential high level of noncompliance; malignant hypertension; hypersensitivity to any component of the product.
Dosage and Administration
Adults
IV/PO 2 to 5 mg/day initially; adjust daily dose according to INR determinations. Usual maintenance dosage is 2 to 10 mg/day. Lower dosages are recommended in elderly and/or debilitated patients. Dosage requirements are variable in patients with genetic variations in CYP2C9 and VKORC1 enzymes. For more information on the range of expected therapeutic warfarin doses based on CYP2C9 and VKORC1 genotypes, refer to the manufacturer's prescribing information.
Duration of therapy
The following duration of therapy recommendations are based on the 9th American College of Chest Physicians (ACCP) Conference on Antithrombotic and Thrombolytic Therapy.
Atrial fibrillation
Indefinite.
Bioprosthetic valves in the mitral position
3 mo after valve insertion.
Anterior myocardial infarction with left ventricular thrombus or high risk of left ventricular thrombus
3 mo after the MI.
Venous thromboembolism First episode, transient (reversible) risk factor
3 mo.
First episode, unprovoked
At least 3 mo; eva luate risk-benefit of long-term therapy.
Two or more episodes of documented deep venous thrombosis or pulmonary embolism
Indefinite; periodically reassess the risk-benefit of anticoagulation. For patients at high risk of bleeding who have a second unprovoked venous thromboembolism, 3 mo of therapy is recommended.
INR goals
The following INR goals are based on the 9th ACCP Conference on Antithrombotic and Thrombolytic Therapy recommendations.
Atrial fibrillation or flutter; anterior myocardial infarction and left ventricular thrombus or at high risk of left ventricular thrombus
2 to 3.
Mechanical heart valve in aortic and mitral position
3 (range, 2.5 to 3.5).
Mechanical valve in aortic position; bioprosthetic valve in the mitral position; rheumatic mitral valve disease and normal sinus rhythm with left atrial diameter more than 55 mm; rheumatic mitral valve disease complicated by atrial fibrillation, previous systemic embolism, and/or left atrial thrombus; venous thromboembolism (including deep vein thrombosis and pulmonary embolism)
2.5 (range, 2 to 3).
Elderly
PO/IV Lower initiation and maintenance doses are recommended.
General Advice
•Routine use of loading doses is not recommended.
•Tablets can be broken in half for more flexible dosing.
•For IV use, give a slow bolus injection over 1 to 2 min in a peripheral vein; not recommended for IM administration.
•Reconstitute IV vial with 2.7 mL of sterile water for injection to yield 2 mg/mL.
Storage/Stability
Store between 59° and 86°F. Protect from light. After reconstitution, store IV solution between 59° and 86°F and use within 4 h. Do not refrigerate. Discard any unused IV solution.